Substrain and sex differences in circle of Willis anatomy. (a)
Examples of posterior communicating artery (PcomA) scoring. Arrows
indicate PcomA. Vascular caliber was graded from 0 to 3, and
communication was subsequently rated as poor (grade 0 or 1) or
robust (grade 2 or 3) as described in the text. These examples were
perfused with blue silicone. (b) Sex and substrain differences in
the distribution of PcomA scores. Results did not differ between NJ
and NCrl, or between J and JEiJ, so results are pooled to simplify
presentation. The right PComA was comparably developed in males of
all substrains. Female NJ/NCrl and J/JEiJ mice exhibited PcomA
scores comparable to males of the same substrains, whereas all
female ByJ had robust communication. Left PcomA scores showed the
same pattern of strain variation as the right with the striking
exception of ByJ males, in which the left PcomA exhibited the
consistent patency seen bilaterally in ByJ females. Numbers of NJ,
NCrl, J, JEiJ and ByJ mice were 9, 9, 12, 15 and 10 males, and 4, 8,
13, 9 and 14 females, respectively.